Fair Value Measurements (Assets of Pension Plans Measured at Fair Value on a Recurring Basis) (Details) (Fair Value, Measurements, Recurring, USD $) In Thousands, unless otherwise specified	Mar. 31, 2013	Mar. 31, 2012
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of plan assets at end of period	$ 497,575	$ 472,316
Equity funds - international-based companies
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of plan assets at end of period	113,655	105,157
Cash and cash equivalents
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of plan assets at end of period	11,536	6,067
Equity funds - U.S.-based companies
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of plan assets at end of period	87,466	79,800
Fixed income funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of plan assets at end of period	282,582	277,528
Other
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of plan assets at end of period	2,336	3,764
Quoted Price in Active Markets for Identical Assets (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of plan assets at end of period	11,536	6,067
Quoted Price in Active Markets for Identical Assets (Level 1) | Equity funds - international-based companies
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of plan assets at end of period	0	0
Quoted Price in Active Markets for Identical Assets (Level 1) | Cash and cash equivalents
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of plan assets at end of period	11,536	6,067
Quoted Price in Active Markets for Identical Assets (Level 1) | Equity funds - U.S.-based companies
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of plan assets at end of period	0	0
Quoted Price in Active Markets for Identical Assets (Level 1) | Fixed income funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of plan assets at end of period	0	0
Quoted Price in Active Markets for Identical Assets (Level 1) | Other
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of plan assets at end of period	0	0
Significant Other Observable Inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of plan assets at end of period	486,039	466,249
Significant Other Observable Inputs (Level 2) | Equity funds - international-based companies
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of plan assets at end of period	113,655	105,157
Significant Other Observable Inputs (Level 2) | Cash and cash equivalents
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of plan assets at end of period	0	0
Significant Other Observable Inputs (Level 2) | Equity funds - U.S.-based companies
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of plan assets at end of period	87,466	79,800
Significant Other Observable Inputs (Level 2) | Fixed income funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of plan assets at end of period	282,582	277,528
Significant Other Observable Inputs (Level 2) | Other
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of plan assets at end of period	2,336	3,764
Significant Unobservable Inputs (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of plan assets at end of period	0	0
Significant Unobservable Inputs (Level 3) | Equity funds - international-based companies
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of plan assets at end of period	0	0
Significant Unobservable Inputs (Level 3) | Cash and cash equivalents
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of plan assets at end of period	0	0
Significant Unobservable Inputs (Level 3) | Equity funds - U.S.-based companies
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of plan assets at end of period	0	0
Significant Unobservable Inputs (Level 3) | Fixed income funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of plan assets at end of period	0	0
Significant Unobservable Inputs (Level 3) | Other
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of plan assets at end of period	$ 0	$ 0